Perceptual Processes:
Visual & Auditory Recognition
Dr. Claudia J. Stanny
EXP 4507
Memory & Cognition
Spring 2009
Perception
• Distal stimulus
• Proximal stimulus
• Sensory memory
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Iconic memory
Echoic memory
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Iconic Memory
• Perceptually detailed visual memory
• Duration is very short ( .5 sec - 1 sec)
• Information stored has not been analyzed yet
for meaning
• Precategorical sensory information
• Content can be cued effectively based on sensory
qualities, not meaning
Echoic Memory
Auditory analog to iconic memory
Precategorical auditory (sensory) information
• Can cue recall of selected items based on
sensory qualities but not based on meaning
Very short duration (approximately 2 sec)
Sensory Processes & the Brain
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Gestalt Psychology: Organizing Principles
in Perception
Form perception
Figure-ground resolution
Detection of contours (subjective contours)
Principles of organization
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Proximity
Similarity
Good continuation
Closure
Common fate
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Object Recognition
• Template-matching models
• Feature analysis models
• Recognition-by-components models
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Template-Matching Models
Effective for pattern
recognition for small sets
of well-defined patterns
Template matching used
today for pattern
recognition of bank codes
on checks
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Feature Analysis Models
Selfridge (1958) Pandemonium
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Feature Analysis Models
Relies on simpler features
for template matching
Includes a system of rules
for how features are
combined to create specific
patterns
Draws on single-unit data for
neurons responding to
sensory input (e.g., work by
Hubel & Wiesel, 1965, 1979,
2005)
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Recognition-by-Components
Models
Similar to feature analysis
models
Developed for perception
of 3-dimensional objects
Biederman (1990)
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Top-Down & Bottom-Up
Processing
• Bottom-up processing
• Emphasis on sensory input
• Raw sensory input → pattern recognition
• Top-down processing
• Emphasis on concepts and expectations
• Expectations and context create biases to extract
certain patterns from sensory input
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Errors in Perception
• Levin & Simons (1997, 2000)
• Change blindness
• Inattention blindness
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Change Blindness Demonstration
Links to Videos
Magic Trick
http://www.youtube.com/watch?v=voAntzB7EwE
Harvard: Participants signing up for an
experiment
http://www.youtube.com/watch?v=mAnKvo-fPs0
Original Door Study (Levin & Simon, 1997)
http://viscog.beckman.uiuc.edu/flashmovie/12.php
Recreation of Simon’s Door Experiment
http://www.youtube.com/watch?v=p1aEqBaK3aM
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Face Recognition
Perception of faces
Prosopagnosia
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Thatcher Illusion
Based on tendency to process faces holistically
When faces are viewed upside down, we might
not detect alterations in component parts
When faces are viewed right side up, these
changes are easily detected
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Speech Perception
• Phoneme recognition
• Detection of word boundaries
• Constructive nature of speech perception
• Context effects on speech recognition
• Phonemic restoration
• McGurck effect
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Theories of Speech Perception
• Speech perception as a special mechanism of
the brain
• Speech perception as characteristic of general
perceptual mechanisms
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